Summary
Recently, a broad sector of the industry has come together in a call-to-action on harvest equipment cleaning and sanitation performance and standardization of performance criteria. Across the key states currently named within the FDA Assignment (CA, AZ, and FL), several leading firms have expressed interest to be enrolled in a baseline assessment of field harvest equipment in relation to the development of standards of industry-practice for “What is clean?”. In an effort to support industry with near real-time data, the research and extension team has recruited industry partners to participate in this study to assess harvest machine cleaning and sanitation practices across California, Arizona, and Florida. We have targeted the following machine types for participation in the study; self-propelled Ramsay Highlander, three-point tractor mount, and tender leaf self-propelled. The research teams in each state (CA, AZ, FL) are coordinating on-site assessments with growers, handlers, and/or contract harvest operations across multiple harvesting events. Data being collected includes crop, acres, and temporal factors associated with each harvest event, information related to the harvest including storage location, run time, time between end-of-harvest and cleaning & sanitizing activities. Finally, information related to the sanitation practices including sanitizer used (residual ppm), source water used (w COA), as well as a sanitary design review – ranking based on age, design, and ability to clean and sanitize is also being collected. In addition to the above collected data, the research and extension teams are also conducting bacterial swabs to assess surface prevalence (presence/absence) and concentration for a variety of indicator organisms including the following; ATP (Charm Field Format), Aerobic Plate Count (APC), generic E. coli, and Total Coliform bacteria. For interested participants, Listeria sp. swabs are also being collected, with samples held until the season has ended and product has moved through the marketplace. For each event, 15 to 30-point swabs are collected during each of three time points; (1) post-harvest, (2) post-cleaning, and (3) post-sanitation. Overall prevalence, and prevalence over time, will be reported as an output in aggregated form. Ultimately, the intent of this research project is to develop a dynamic, aggregated, and confidential dataset from which to offer leafy greens growers, shippers, handlers, harvest contractors, and processors to integrate outcomes into “real-time” opportunities for continual improvements and preparedness for audits and inspections.
Research Objectives
Over the course of this project, the research and extension team aim to identify potential “hot spot” locations on harvest equipment and successful mitigation measures to address these issues. An underlying goal is to adapt or develop, as necessary, a standard set of terms for C&S operations transferable and applicable to multiple types of field harvest equipment based on the CFS Harvest Forward white paper (request from CFS ). In addition, the anticipated outcome will include a standardized criteria for comparative performance verification of both C&S crews and diverse contact and non-contact surfaces. Lastly, discussion with industry has identified an interest in developing science-based information on alternatives to ATP-bioluminescence in on-site determination of “clean for the intended purpose”.
Findings & Recommendations
The recommendations for improving harvest equipment cleaning and sanitation practices include the following: 1. Detergent and Equipment Impact: o Detergent type and application, as well as the tools used during cleaning, have a greater impact on microbial reductions than sanitizers alone. o Chlorination detergents significantly increased ATP, Total Coliform bacteria and generic E. coli reductions, making them effective for cleaning and sanitation purposes. 2. Cleaning Steps and Procedures: o The cleaning (detergent) step itself has the most significant impact on reducing Aerobic Plate Count bacteria and ATP on harvest machines. o It is crucial to standardize the cleaning process from one side to the other and focus on a top-down cleaning approach to reduce potential cross-contamination risks. 3. Crew Management: o Managing the number of dedicated crew members and their cleaning protocols can help minimize cross contamination. For example, it is recommended to avoid simultaneous cleaning of both sides of the machine and instead clean systematically from the top down. 4. Real-Time Evaluation: o ATP can be used effectively to evaluate cleaning and sanitation effectiveness in real time, aiding in immediate corrective actions if needed. 5. Worker Training and Education: o Continuous improvements on the reduction of bacterial concentrations and the percentage of positive samples were observed throughout the study, highlighting the impact of ongoing worker training and education on reducing microbiological presence on harvest machines. 6. Opportunities for Improvement: o Simple changes, such as the availability of ladder/platform, dedicated brushes, verification tools, dedicated employee time, appropriate chemicals (foamers, coverage, contact times), and highlighting areas of concern to cleaning crews, can significantly improve cleaning and sanitation effectiveness. 7. Microbial Sampling and Analysis: o This study included systematic sampling at various points on the harvest machines and tested for indicators like Adenosine Triphosphate (ATP), Aerobic Plate Count bacteria (APC), generic E. coli (gEC), and Total Coliform bacteria (TC) to measure the effectiveness of the cleaning and sanitation procedures. o APC values correlate the most strongly with ATP values using a pairwise function with a confidence level of 0.95. o While not suggested as mandatory inclusion in industry SOPs, collection of baseline microbiological monitoring data could be useful to support worker training and evaluation of cleaning and sanitation procedures for industry. These recommendations aim to provide a standardized approach to cleaning and sanitation that can be integrated into real-time operations, leading to continual improvements and better preparedness for audits and inspections in the leafy greens industry.
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